A remote
sensing study of the Northern Negros Geothermal Project (NNGP)
was conducted using Airborne Synthetic Aperture Radar (AIRSAR)
images that have the ~ 10 - meter spatial resolution of
traditional aerial photographs. A digital elevation model (DEM)
was generated from the topographic SAR (TOPSAR) data sets while
the general surface geology was extracted from the polarimetric
SAR (POLSAR) data sets.
Northwest - trending lineaments
form the dominant structural grain in the study area. This
tectonic fabric is expressed by lineaments with the following
trends: northwest (293° - 337°),
west - northwest (270 ° - 292°)
and north - northwest (338° -
360°). The northwest and west
- northwest structures control the occurrence of thermal springs
(e.g. Mambucal thermal area and Hagdan hot spring, respectively)
while the north - northwest structures are associated with the
distribution of volcanic vents and are strongly related to the
eastward subduction along the Negros Trench. In addition, nine
geologic units were outlined within the study area as volcanic
products generated from the Canlaon Volcano.
Major structures such as
Catugasan - C, Mambucal - A and Asia Splay A faults which were
intersected by Pataan boreholes PT-1D, PT-2D, PT-3D and PT-4D
represent the major permeable zones in the wells. It is prudent
to target similar - trending structures for future production
and reinjection purposes.
The integrated results of the
geological, geochemical and geophysical surveys indicate that
the upflow of the geothermal system is within the Hardin Sang
Balo area. The upflow is structurally - bounded by the
southeastern segments of Mambucal - A and Asia Splay Extension
while the outflow is channeled along the Catugasan - C and
Catugasan - B Splay faults towards NW in the general direction
of the Kinabkaban warm spring and Mambucal thermal area.
Drilling towards the east -
southeast direction (from Pataan - B pad) is favored to
intersect high temperature geothermal fluids and to test the
postulated hydrological model of NNGP.